From: Theodore Ts'o <tytso@mit.edu>
To: "Cristian Rodríguez" <crrodriguez@opensuse.org>
Cc: linux-ext4@vger.kernel.org
Subject: Re: [PATCH] lib/ext2fs: Use __builtin_popcount when available Signed-off-by: Cristian Rodríguez <crrodriguez@opensuse.org>
Date: Sun, 6 Jan 2013 20:31:56 -0500 [thread overview]
Message-ID: <20130107013156.GB12838@thunk.org> (raw)
In-Reply-To: <50EA1C9B.8040304@opensuse.org>
On Sun, Jan 06, 2013 at 09:53:47PM -0300, Cristian Rodríguez wrote:
>
> Yeah, I asked GCC developers exactly this, was told to fill a
> enhancement request.
If you could also sned them a bug/enhancement request to use a more
optimized version of __popcountdi2, that would be great. I'm not sure
it helps e2fsprogs much, since it's too hard for us to tell whether we
are using a version of the gcc runtime that has a optimized or
unuptomized version of builtin_popcount().
But since it doesn't make that much difference, my preference is to
just ignore builtin_popcount() for now. If someone is really using
128TB ext4 file systems, and cares about that extra 6 seconds of CPU,
it's probably going to require the ugly approach of using x86 asm
statements to determine whether or not we're running on a CPU that
supports the popcount instruction or not....
- Ted
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2013-01-07 1:32 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-06 15:04 [PATCH] lib/ext2fs: Use __builtin_popcount when available Signed-off-by: Cristian Rodríguez <crrodriguez@opensuse.org> Cristian Rodríguez
2013-01-06 22:20 ` Theodore Ts'o
2013-01-07 0:53 ` Cristian Rodríguez
2013-01-07 1:31 ` Theodore Ts'o [this message]
2013-01-07 1:46 ` Cristian Rodríguez
2013-01-07 1:56 ` Theodore Ts'o
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20130107013156.GB12838@thunk.org \
--to=tytso@mit.edu \
--cc=crrodriguez@opensuse.org \
--cc=linux-ext4@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.